Hamid Karzai, Afghanistan's president, has been forced to cut short a speech at a Kabul stadium after sounds that seemed liked gunshots were heard.

Witnesses said Karzai was hastily led away from the ceremony at the sports stadium by his US-trained bodyguards.

A government official urged the audience to be calm, saying that stones were thrown by people who could not get into the stadium.

Zahir Azimi, the defense ministry spokesman, said that "thousands" of people had been pushing the gates and throwing stones, demanding to be allowed into the venue.

Alan Fisher, Al Jazeera's correspondent in Kabul, said there was speculation that Afghan security guards could have fired in the air to disperse the crowd. Afghan officials, however, say they did not fire.

Abrupt end

"Dear brothers and sisters, with respect to everybody, we are finishing our ceremony here," Karzai said as he left the stage.

An estimated 25,000 people, including cabinet members and foreign diplomats had gathered at the stadium which is located near the presidential palace.

The ceremony was held to mark the sixth anniversary of the death of Ahmad Shah Masood, a military leader of an anti-Taliban alliance, killed by a suspected al-Qaeda suicide bomber two days before the September 11 attacks in the United States.

Kabul's already tight security is usually heightened for major events, amid fears of attacks by Taliban fighters.

PHOTO CAPTION

Hamid Karzai, Afghanistan's president